CA1159937A - High-energy laser of the tea type with pre-ionization tubes disposed axially parallel to the laser - Google Patents
High-energy laser of the tea type with pre-ionization tubes disposed axially parallel to the laserInfo
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- CA1159937A CA1159937A CA000386280A CA386280A CA1159937A CA 1159937 A CA1159937 A CA 1159937A CA 000386280 A CA000386280 A CA 000386280A CA 386280 A CA386280 A CA 386280A CA 1159937 A CA1159937 A CA 1159937A
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- electrodes
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- shaped
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/02—Constructional details
- H01S3/04—Arrangements for thermal management
- H01S3/041—Arrangements for thermal management for gas lasers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/02—Constructional details
- H01S3/03—Constructional details of gas laser discharge tubes
- H01S3/038—Electrodes, e.g. special shape, configuration or composition
- H01S3/0385—Shape
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/097—Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser
- H01S3/0971—Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser transversely excited
- H01S3/09713—Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser transversely excited with auxiliary ionisation, e.g. double discharge excitation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/02—Constructional details
- H01S3/03—Constructional details of gas laser discharge tubes
- H01S3/038—Electrodes, e.g. special shape, configuration or composition
- H01S3/0384—Auxiliary electrodes, e.g. for pre-ionisation or triggering, or particular adaptations therefor
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
Abstract
Abstract of the Disclosure:
High energy laser of the TEA type, including a discharge tube having an optical axis of the laser and a gas discharge space formed therein, at least two main electrodes being spaced apart and oppo-sitely disposed in the discharge tube and extended parallel to the optical axis, excitation being carried out by condenser discharge being free of arcs and as homogeneous as possible in the gas dis-charge space between the electrodes, at least one of the main electrodes having a mushroom-shaped cross section with a mushroom-shaped stem for current conduction and a mushroom-shaped hat for current distribution and being extended into the gas discharge space, ant at least one rod-shaped auxiliary electrode being disposed parallel to the optical axis and at a given sparkover distance from one of the electrodes, for pre-ionization of the gas discharge space, the at least one auxiliary electrode having an inner conductor and a dielectric surrounding the inner conductor.
LAG/amm.
High energy laser of the TEA type, including a discharge tube having an optical axis of the laser and a gas discharge space formed therein, at least two main electrodes being spaced apart and oppo-sitely disposed in the discharge tube and extended parallel to the optical axis, excitation being carried out by condenser discharge being free of arcs and as homogeneous as possible in the gas dis-charge space between the electrodes, at least one of the main electrodes having a mushroom-shaped cross section with a mushroom-shaped stem for current conduction and a mushroom-shaped hat for current distribution and being extended into the gas discharge space, ant at least one rod-shaped auxiliary electrode being disposed parallel to the optical axis and at a given sparkover distance from one of the electrodes, for pre-ionization of the gas discharge space, the at least one auxiliary electrode having an inner conductor and a dielectric surrounding the inner conductor.
LAG/amm.
Description
1 159~J7 HIGH-ENERGY LASER OF THE TEA TYPE WITH PRE-IONIZA~ION TUBES DISPOSED AXIALLY
PARP,L~ TO TH~3 I~:R
Specificatian:
The invention relates to a high~energy laser of the TE~ Type, especi-ally a TEA Excimer laser with excitation carried out by a condenser discharge being free of arcs and as homDgeneous as possible in the gas space betwe~n at least two electrodes of a discharge tube extending parallel to the optical axis of the laser and disposed opposite each other at a spacing, at least one of which has a mushroomrshaped cross section.
U.S. Patent No. 4,365,337, issued December 21, 1982, which will be re-ferred to as No. (1), proposes an excitation system for fast pulse discharge, andin particular a high-energy laser of the TE~-type which is distinguished by very low self inductan oe and high switching capacity. The shape of the laser elec-trodes, hcwover, can perhaps be called approximately mushroom-shaped. Electrodes with mushroom~shaped cross sections are known fm m the journal "Electronics Letters", March 25, 1971, vol. 7, pp. 141,142, referred to as (2); and further-mDre through the journal "Applied Physics Letters", vol. 29 of De oe mber 1, 1976, pp. 707 to 709, referred to herein as (3). It is also kncwn fro~ (2) to give the laser electrodes a so-called Rogowski profile in order to obtain an improved field distribution and homDgeneity of the discharge. The same purpose is served by the so-called Chang profile, seen in the journal " m e Review of Scientific Instruments", vol. 44, of April 1973, pp. 405 to 407, which will be given No. (4).
m e present invention is also con oe rned with the problem of obtaIning the largest and m~st hcrlx~oeous discharge cross section ,~
1 159g37 perpe~ndicular to the optical axis and the longitudinal direction of the electrodes that is possible in TEA lasers. This is ~Q be accomplished by a suitable construction of the electrodes and through the use of an effective pre-ionization unit. As has been shown, the discharge in the TEA-Excimer lasers known so far still has the tendency to be split into several individual regions although the laser electrodes with mushroom cross sections have already brought an improvement.
It is accordingly an object of the invention to provide a high-energy laser of the TEA type with pre-ionization tubes disposed axially parallel to the laser, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type, and particularly a TEA-Excimer laser with respect to a discharge cross section that is as large as possible and homogeneous. This is of particular importance because the emphasis of use of TEA lasers has shifted more and more into the industrial area, and thus questions of econ~my and therefore of the efficiency and the optical energy of a single'pulse are coming more and more to the forefront~
With the foregoing and other objects in view there is provided, in accordance with the invention, a high energy laser of the TEA
type, especially a TEA Excimer laser, comprising a discharge tube having an optical axis of the laser and a gas discharge space formed therein, at least two main electrodes being spaced apart and oppositely disposed in the'discharge'tube'and extended parallel 1 1599~7 to t'he optical axis, excitation being carried out by condenser dis-charge being free of arcs and as homogeneous as possible in the gas discharge space between the electrodes, at least one of the main electrodes having a mushroom-shaped cross section with a mushroom-shaped stem for current conduction and a mushroom-shaped hat for current distribution and being extended into the gas dis-charge space,' and at least one rod-shaped auxiliary eIectrode being disposed paralleI to the'optical axis between or adjacent to the electrodes and at a given sparkover distance from one of the'electrodes, for pre-ion'ization of the gas discharge space,the at least one'auxiliary electrode having an inner~ conductor and a dielectric surrounding the'inner conductor.
In accordance with another feature of thé invention, two of the mushroom-shaped eIec~rodes are'disposed facing each other with the'mushroom-shaped hats in mirror symmetry, at least one of the mushroom-shaped hats of the at least two main electrodes having two of th.e auxiliary el'ectrodes associated therewith.
In accordance with'a further feature of the invention, thé main electrodes are'pierced by cooling canals formed therein being ex-tended paralleI to the'optical axis.
In accordance with an added feature of the invention, the mush-room-shaped hats are'in the'form of screen electrodes formed of perforated she'et metal.
In accardance with an addi.tional feature of the invention, the 1 1S9~
auxi].iary electrodes are formed in niches between mushroom-shaped hats and mushroom-shaped stems.
In accordance with again another feature of the invention, the inner conductor of the auxiliary electrodes is cylindrical and the dielectric surrounding the conductor is hollow!and cylindrical.
In accordance with again a further feature of the invention, the mushroom-shaped electrodes have a Chang profile In accordance with again an added feature of the invention, the mushroom-shaped electrodes have a Rogowski profile.
In accordance with again an additional feature of the invention, the dielectric is high voltage-proof and is formed of a material from the group consisting of BaTiO3, SrTiO3, A1203 and BeO.
In accordance with a concomitant feature of the invention, there is provided a Blumlein charge transer circuit, the inner conductor of the pre-ionization rod-shaped auxiliary electrodes being con-nected to and opposite one of the main electrodes in the circuit in a conducting manner.
The advantages attainable with the invention are in particular that through the orientation of the mushroom hat parallel to the laser axis, ~he mushroom stem, and the rod-shaped auxiliary electrode, a very uniform pre-ionization and therefore main discharge as well can be achieved without splitting the discharge into the individual regions.
1 159~7 Other features which are considered as characteristic for ~he inventlon are se~ forth in the appended claims.
Although the invention is illust~ated and described herein as embodied in high energy laser of:the TEA-tyPe with pre-ionization tubes disposed axially parallel to the 'laser, it i~ nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the'spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the inventionJ however, together with additional objects and advantages thereof will be best understood from thé following description of specific mbodi-ments when read in connection with the accompanying drawings, in which:
Fig. 1 is a simplified diagrammatic cross-sectional view of a la~er tube with two opposite mirror-symmetrical mushroom-shaped laser eIectrodes, each including a pre-ionization auxiliary pair of electrodes;
Fig. 2 is a cross-sectional view of a variant embodiment of the laser electrode construction with a mushroom hat of screen electrodes formed of perforated sheet metal;
Fig. 3 is a cross-sectional view of a rod-shaped auxiliary elec-trode;
Fig. 4 iB a diagrammatic and schemat'ic pulse'circuît-diagram for -5- ' .!
generating the pre-ionization and main discharge pulses in the form of a Blumlein-circuit; and Fig. 5 is another diagrammatic and schematic pulse circuit diagram in the form of a charge-transfer circuit for generating the firing pulses.
Referring now to the figures of the drawing and first particularly to Fig. 1 thereof, it is seen that the high-energy laser of the ~EA type (TE~ laser meaning "transversely excited atm~spheric pressure laser") is constructed in such a way that, in a gas spa oe 1 between the two electrodes of the laser or dis-charge tube 3 which extend p æ allel to the optical axis 2 of the laser and are disposed opposite each other at a distan oe al, an æ c-free condenser discharge which is as homogeneous as possible takes plaoe . The approximately rectangul æ
housing 3a of the laser which is designated as a whole with referenoe character L, is assembled in a gas-tight manner from ceramic walls 3al, 3a2, 3a3 and 3a4, which preferably are formed of high-purity A1203 ceramic. The laser gas has a oomposition such as is described for instance in U.S. Patent No. 4,365,337, issued Deoember 21, 1982. The electrcdes El, E2 each extend with a mushroo~
shaped stem 4 serving as the current lead and a m~shroomrshaped hat 5 serving for the distribution of the current. The stem and hat extend into the discharge or gas space 1 and have tabs 6 brought through the walls 3al, 3a2 to the outside.
For pre-ionizating of the discharge spa oe 1, rod-shaped auxiliary elec~rodes Hll, H12, are disposed between the electrodes El, l 159937 E2 immediately adjacent to the mushroom-shaped hat 5 of the electrode El, and auxiliar~ electrodes H21, H22 are disposed immediately adjacent to the mushroom-shaped hat 5 of the electrode E2. Each of the auxiliary electrodes`are located at a sparkover distance a2 from the electrodes. I~mediately prior to the firing of the laser, a sparkover between the surrounding dielectric of the auxiliary electrodes Hll, H12, H21, H22 and the associated electrodes El and E2, respectively, takes place. The ~V light emit-ted by the sparks ionizes the gas enclosed by the electrodes El and E2. The electrodes El, E2 are disposed opposite each other, with their mushroom-shaped hats 5 in mirror symmetry as can be seen. The two auxiliary electrode pairs Hll, H12 and H21, H22 are disposed opposite each other in mirror symmetry. This arrange-ment is particularly advantageous for obtaining a discharge cross section which is as large and as homogeneous as possible.
According to Fig. 3, the auxiliary electrodes designated with reference character H have rod-shaped inner conductor 7,which is made of copper, for instance, and a dielectric 8 formed as a circular ring enclosing the inner conductor 7, which is preferably a high purity BaTiO3, SrTiO3~ A12Q3 or BeO ceramic as well~. These auxiliary electrodes H are fastened at the ends thereof in a suit-able manner to the non-illustrated end walls of the laser chamber 3 of Fig. 1. Cooling canals 9 pass through the laser electrodes El, E2, i.e. the mushroom-shaped hats 5 and the mushroom-shaped stems 4.
The cooling canals 9 preferably extend parallel to the optical axis
PARP,L~ TO TH~3 I~:R
Specificatian:
The invention relates to a high~energy laser of the TE~ Type, especi-ally a TEA Excimer laser with excitation carried out by a condenser discharge being free of arcs and as homDgeneous as possible in the gas space betwe~n at least two electrodes of a discharge tube extending parallel to the optical axis of the laser and disposed opposite each other at a spacing, at least one of which has a mushroomrshaped cross section.
U.S. Patent No. 4,365,337, issued December 21, 1982, which will be re-ferred to as No. (1), proposes an excitation system for fast pulse discharge, andin particular a high-energy laser of the TE~-type which is distinguished by very low self inductan oe and high switching capacity. The shape of the laser elec-trodes, hcwover, can perhaps be called approximately mushroom-shaped. Electrodes with mushroom~shaped cross sections are known fm m the journal "Electronics Letters", March 25, 1971, vol. 7, pp. 141,142, referred to as (2); and further-mDre through the journal "Applied Physics Letters", vol. 29 of De oe mber 1, 1976, pp. 707 to 709, referred to herein as (3). It is also kncwn fro~ (2) to give the laser electrodes a so-called Rogowski profile in order to obtain an improved field distribution and homDgeneity of the discharge. The same purpose is served by the so-called Chang profile, seen in the journal " m e Review of Scientific Instruments", vol. 44, of April 1973, pp. 405 to 407, which will be given No. (4).
m e present invention is also con oe rned with the problem of obtaIning the largest and m~st hcrlx~oeous discharge cross section ,~
1 159g37 perpe~ndicular to the optical axis and the longitudinal direction of the electrodes that is possible in TEA lasers. This is ~Q be accomplished by a suitable construction of the electrodes and through the use of an effective pre-ionization unit. As has been shown, the discharge in the TEA-Excimer lasers known so far still has the tendency to be split into several individual regions although the laser electrodes with mushroom cross sections have already brought an improvement.
It is accordingly an object of the invention to provide a high-energy laser of the TEA type with pre-ionization tubes disposed axially parallel to the laser, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type, and particularly a TEA-Excimer laser with respect to a discharge cross section that is as large as possible and homogeneous. This is of particular importance because the emphasis of use of TEA lasers has shifted more and more into the industrial area, and thus questions of econ~my and therefore of the efficiency and the optical energy of a single'pulse are coming more and more to the forefront~
With the foregoing and other objects in view there is provided, in accordance with the invention, a high energy laser of the TEA
type, especially a TEA Excimer laser, comprising a discharge tube having an optical axis of the laser and a gas discharge space formed therein, at least two main electrodes being spaced apart and oppositely disposed in the'discharge'tube'and extended parallel 1 1599~7 to t'he optical axis, excitation being carried out by condenser dis-charge being free of arcs and as homogeneous as possible in the gas discharge space between the electrodes, at least one of the main electrodes having a mushroom-shaped cross section with a mushroom-shaped stem for current conduction and a mushroom-shaped hat for current distribution and being extended into the gas dis-charge space,' and at least one rod-shaped auxiliary eIectrode being disposed paralleI to the'optical axis between or adjacent to the electrodes and at a given sparkover distance from one of the'electrodes, for pre-ion'ization of the gas discharge space,the at least one'auxiliary electrode having an inner~ conductor and a dielectric surrounding the'inner conductor.
In accordance with another feature of thé invention, two of the mushroom-shaped eIec~rodes are'disposed facing each other with the'mushroom-shaped hats in mirror symmetry, at least one of the mushroom-shaped hats of the at least two main electrodes having two of th.e auxiliary el'ectrodes associated therewith.
In accordance with'a further feature of the invention, thé main electrodes are'pierced by cooling canals formed therein being ex-tended paralleI to the'optical axis.
In accordance with an added feature of the invention, the mush-room-shaped hats are'in the'form of screen electrodes formed of perforated she'et metal.
In accardance with an addi.tional feature of the invention, the 1 1S9~
auxi].iary electrodes are formed in niches between mushroom-shaped hats and mushroom-shaped stems.
In accordance with again another feature of the invention, the inner conductor of the auxiliary electrodes is cylindrical and the dielectric surrounding the conductor is hollow!and cylindrical.
In accordance with again a further feature of the invention, the mushroom-shaped electrodes have a Chang profile In accordance with again an added feature of the invention, the mushroom-shaped electrodes have a Rogowski profile.
In accordance with again an additional feature of the invention, the dielectric is high voltage-proof and is formed of a material from the group consisting of BaTiO3, SrTiO3, A1203 and BeO.
In accordance with a concomitant feature of the invention, there is provided a Blumlein charge transer circuit, the inner conductor of the pre-ionization rod-shaped auxiliary electrodes being con-nected to and opposite one of the main electrodes in the circuit in a conducting manner.
The advantages attainable with the invention are in particular that through the orientation of the mushroom hat parallel to the laser axis, ~he mushroom stem, and the rod-shaped auxiliary electrode, a very uniform pre-ionization and therefore main discharge as well can be achieved without splitting the discharge into the individual regions.
1 159~7 Other features which are considered as characteristic for ~he inventlon are se~ forth in the appended claims.
Although the invention is illust~ated and described herein as embodied in high energy laser of:the TEA-tyPe with pre-ionization tubes disposed axially parallel to the 'laser, it i~ nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the'spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the inventionJ however, together with additional objects and advantages thereof will be best understood from thé following description of specific mbodi-ments when read in connection with the accompanying drawings, in which:
Fig. 1 is a simplified diagrammatic cross-sectional view of a la~er tube with two opposite mirror-symmetrical mushroom-shaped laser eIectrodes, each including a pre-ionization auxiliary pair of electrodes;
Fig. 2 is a cross-sectional view of a variant embodiment of the laser electrode construction with a mushroom hat of screen electrodes formed of perforated sheet metal;
Fig. 3 is a cross-sectional view of a rod-shaped auxiliary elec-trode;
Fig. 4 iB a diagrammatic and schemat'ic pulse'circuît-diagram for -5- ' .!
generating the pre-ionization and main discharge pulses in the form of a Blumlein-circuit; and Fig. 5 is another diagrammatic and schematic pulse circuit diagram in the form of a charge-transfer circuit for generating the firing pulses.
Referring now to the figures of the drawing and first particularly to Fig. 1 thereof, it is seen that the high-energy laser of the ~EA type (TE~ laser meaning "transversely excited atm~spheric pressure laser") is constructed in such a way that, in a gas spa oe 1 between the two electrodes of the laser or dis-charge tube 3 which extend p æ allel to the optical axis 2 of the laser and are disposed opposite each other at a distan oe al, an æ c-free condenser discharge which is as homogeneous as possible takes plaoe . The approximately rectangul æ
housing 3a of the laser which is designated as a whole with referenoe character L, is assembled in a gas-tight manner from ceramic walls 3al, 3a2, 3a3 and 3a4, which preferably are formed of high-purity A1203 ceramic. The laser gas has a oomposition such as is described for instance in U.S. Patent No. 4,365,337, issued Deoember 21, 1982. The electrcdes El, E2 each extend with a mushroo~
shaped stem 4 serving as the current lead and a m~shroomrshaped hat 5 serving for the distribution of the current. The stem and hat extend into the discharge or gas space 1 and have tabs 6 brought through the walls 3al, 3a2 to the outside.
For pre-ionizating of the discharge spa oe 1, rod-shaped auxiliary elec~rodes Hll, H12, are disposed between the electrodes El, l 159937 E2 immediately adjacent to the mushroom-shaped hat 5 of the electrode El, and auxiliar~ electrodes H21, H22 are disposed immediately adjacent to the mushroom-shaped hat 5 of the electrode E2. Each of the auxiliary electrodes`are located at a sparkover distance a2 from the electrodes. I~mediately prior to the firing of the laser, a sparkover between the surrounding dielectric of the auxiliary electrodes Hll, H12, H21, H22 and the associated electrodes El and E2, respectively, takes place. The ~V light emit-ted by the sparks ionizes the gas enclosed by the electrodes El and E2. The electrodes El, E2 are disposed opposite each other, with their mushroom-shaped hats 5 in mirror symmetry as can be seen. The two auxiliary electrode pairs Hll, H12 and H21, H22 are disposed opposite each other in mirror symmetry. This arrange-ment is particularly advantageous for obtaining a discharge cross section which is as large and as homogeneous as possible.
According to Fig. 3, the auxiliary electrodes designated with reference character H have rod-shaped inner conductor 7,which is made of copper, for instance, and a dielectric 8 formed as a circular ring enclosing the inner conductor 7, which is preferably a high purity BaTiO3, SrTiO3~ A12Q3 or BeO ceramic as well~. These auxiliary electrodes H are fastened at the ends thereof in a suit-able manner to the non-illustrated end walls of the laser chamber 3 of Fig. 1. Cooling canals 9 pass through the laser electrodes El, E2, i.e. the mushroom-shaped hats 5 and the mushroom-shaped stems 4.
The cooling canals 9 preferably extend parallel to the optical axis
2 of the laser, through which a coolant such as water is pumped.
--7~
l 159937 The inner conductor 7 of the auxiliary electrode H can also be a liquid conductor pumped by a circulating system through the ceramic tu~e 8 for simultaneous cooling.
Fig. 2 shows the construction of perforated mushroom-shaped hats 5' as screen eIectrodes w~ich for this purpose are fonmed of per-forated sheet metal. The auxiliary electrodes H are therefore dis-posed within niches 10 formed ~y the mushroom-shaped hat 5' and the'mushroom-shaped stem ~. In the firing process, the W -radia-tion generated~by the sparkover between the'auxiliary electrodes H
and the mushroom-shaped hat 5' can come in through the screen openings 11 into the'di'sc~arge space between the main electrodes El, E2 and ionize thé'latter.
In the'fired gas di'scharge'or pumping of the laser, the current pulse must flo~ through'thé stem 4 of the mushroom towards the center of the mushroom-shaped hat and can only then be distributed in the hat 5. Preferably, the hat 5 of the electrodes El, E2 is developed as a Chan~ or Ro~owski profile as is known from the literature on electrodes of constant homo~eneous surface field intensity. The dual arran~ement of the mushroom and the auxiliary electrodes is particularly advanta~eous even thoup~h'it is possible in principle to construct only one'of the electrodes El, E2 as a mushroom elec-trode. The pulse'circuit according to Fig. 4 for generating the firing and discharge'pulses is a so-called Blumlein circuit. A
pulse'generator P shown therein includes a hi~h-voltage power supply HV, the voltage'of w~i'ch'can be'applied through'a low inductance switch S to a first charging caPacity Cl. A series circuit including 1 15gg37 a second charging capacity C2 and the laser electrode sections El-E2 `
is shunted across this capacity Cl. A low resistance resistor R is shunted across the latter and connected to ground, which is a high pontential as compared to the resistance value of the fired plasma.
As is seen in Fig. 4, the second poles of the switch S and of the switching capacity Cl are also connected to ground potential, as are the laser electrode E2 and the auxiliary electrodes Hll, H12 associated with the opposite laser electrode. The auxiliary elec-trodes H21,` H22 on the other hand are connected to the oppositely disposed laser electrode El in a conducting manner.
The charge-transfer-circuit according to Fig.5 in which like switching elements carry the same reference symbols as in Fig.4, differs from the circuit according to Fig. 4 particularly by the feature that the second switching capacity is connected in parallel with the laser discharge path El-E2, and that the first switching capacity Cl is connected in series with the low-inductance switch S
and therefore to the high voltage power supply.
In both circuits, a shock-like high voltage discharge is released, by first closing the high voltage switch S which may be a spark gap or a thyratron, through the auxiliary electrodes and then through the laser electrodes, the pulse width, height and phase of which results from the inductive, capacitive and ohmic values of the switching elements and leads.
_9 _
--7~
l 159937 The inner conductor 7 of the auxiliary electrode H can also be a liquid conductor pumped by a circulating system through the ceramic tu~e 8 for simultaneous cooling.
Fig. 2 shows the construction of perforated mushroom-shaped hats 5' as screen eIectrodes w~ich for this purpose are fonmed of per-forated sheet metal. The auxiliary electrodes H are therefore dis-posed within niches 10 formed ~y the mushroom-shaped hat 5' and the'mushroom-shaped stem ~. In the firing process, the W -radia-tion generated~by the sparkover between the'auxiliary electrodes H
and the mushroom-shaped hat 5' can come in through the screen openings 11 into the'di'sc~arge space between the main electrodes El, E2 and ionize thé'latter.
In the'fired gas di'scharge'or pumping of the laser, the current pulse must flo~ through'thé stem 4 of the mushroom towards the center of the mushroom-shaped hat and can only then be distributed in the hat 5. Preferably, the hat 5 of the electrodes El, E2 is developed as a Chan~ or Ro~owski profile as is known from the literature on electrodes of constant homo~eneous surface field intensity. The dual arran~ement of the mushroom and the auxiliary electrodes is particularly advanta~eous even thoup~h'it is possible in principle to construct only one'of the electrodes El, E2 as a mushroom elec-trode. The pulse'circuit according to Fig. 4 for generating the firing and discharge'pulses is a so-called Blumlein circuit. A
pulse'generator P shown therein includes a hi~h-voltage power supply HV, the voltage'of w~i'ch'can be'applied through'a low inductance switch S to a first charging caPacity Cl. A series circuit including 1 15gg37 a second charging capacity C2 and the laser electrode sections El-E2 `
is shunted across this capacity Cl. A low resistance resistor R is shunted across the latter and connected to ground, which is a high pontential as compared to the resistance value of the fired plasma.
As is seen in Fig. 4, the second poles of the switch S and of the switching capacity Cl are also connected to ground potential, as are the laser electrode E2 and the auxiliary electrodes Hll, H12 associated with the opposite laser electrode. The auxiliary elec-trodes H21,` H22 on the other hand are connected to the oppositely disposed laser electrode El in a conducting manner.
The charge-transfer-circuit according to Fig.5 in which like switching elements carry the same reference symbols as in Fig.4, differs from the circuit according to Fig. 4 particularly by the feature that the second switching capacity is connected in parallel with the laser discharge path El-E2, and that the first switching capacity Cl is connected in series with the low-inductance switch S
and therefore to the high voltage power supply.
In both circuits, a shock-like high voltage discharge is released, by first closing the high voltage switch S which may be a spark gap or a thyratron, through the auxiliary electrodes and then through the laser electrodes, the pulse width, height and phase of which results from the inductive, capacitive and ohmic values of the switching elements and leads.
_9 _
Claims (10)
1. High-energy laser of the TEA type, comprising a discharge tube having an optical axis of the laser and a gas dis-charge space formed therein, at least two main electrodes being spaced apart and oppositely disposed in said discharge tube and extended parallel to the optical axis, excitation being carried out by condenser discharge being free of arcs and as homogeneous as possible in said gas discharge space between said electrodes, at least one of said main electrodes having a mushroom-shaped cross section with a mushroom-shaped stem for current conduction and a mushroom-shaped hat for current distribution and being extended into said gas dis-charge space, and at least one rod-shaped auxiliary electrode being disposed parallel to the optical axis and at a given sparkover distance from one of said electrodes, for pre-ionization of said gas discharge space, said at least one auxiliary electrode having an inner conductor and a dielectric surrounding said inner conductor.
2. Laser according to claim 1, wherein two of said mushroom-shaped electrodes are disposed facing each other with said mushroom-shaped hats in mirror symmetry, at least one of said mushroom-shaped hats of said at least two main electrodes having two of said auxiliary electrodes associated therewith.
3. Laser according to claim 1, wherein said main electrodes are pierced by cooling canals formed wherein being extended parallel to the optical axis.
4. Laser according to claim 1, wherein said mushroom-shaped hats are in the form of screen electrodes formed of perforated sheet metal.
5. Laser according to claim 4, wherein said auxiliary electrodes are formed in niches between said mushroom-shaped hats and mushroom-shaped stems.
z
z
6. Laser according to claim 1, wherein said inner conductor of said auxiliary electrodes is cylindrical and said dielectric surrounding said conductor is hollow and cylindrical.
7. Laser according to claim 1. wherein said mushroom-shaped electrodes have a Chang profile.
8. Laser according to claim 1, wherein said mushroom-shaped electrodes have a Rogowski profile.
9. Laser according to claim 1, wherein said dielectric is high voltage-proof and is formed of a material from the group consisting of BaTiO3, SrTiO3, A12O3 and BeO.
10. Laser according to claim 1, including a Bl?mlein charge transfer circuit, said inner conductor of said pre-ionization rod-shaped auxiliary electrodes being connected to and opposite one of said main electrodes in said circuit in a conducting manner.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19803035730 DE3035730A1 (en) | 1980-09-22 | 1980-09-22 | TEA TYPE HIGH-ENERGY LASER WITH LASER AXIS PARALLEL PRE-IONIZING RODS |
| DEP3035730.3 | 1980-09-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1159937A true CA1159937A (en) | 1984-01-03 |
Family
ID=6112574
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000386280A Expired CA1159937A (en) | 1980-09-22 | 1981-09-21 | High-energy laser of the tea type with pre-ionization tubes disposed axially parallel to the laser |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0048407A1 (en) |
| JP (1) | JPS5788789A (en) |
| AR (1) | AR227437A1 (en) |
| AU (1) | AU539326B2 (en) |
| BR (1) | BR8106008A (en) |
| CA (1) | CA1159937A (en) |
| DE (1) | DE3035730A1 (en) |
| IL (1) | IL63897A0 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4718072A (en) * | 1983-12-29 | 1988-01-05 | Enea - Comitato Nazionale Per La Ricerca E Lo Sviluppo Della Energia Nucleare E Delle Energie Alternative | Corona discharge preionizer for gas laser |
Families Citing this family (27)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3104229A1 (en) * | 1981-02-06 | 1982-08-19 | Kraftwerk Union AG, 4330 Mülheim | METHOD FOR GENERATING LASER BEAMS IN THE 16 (ARROW DOWN) / (ARROW DOWN) AROUND THE WAVELENGTH AREA |
| DE3126375C2 (en) * | 1981-07-03 | 1986-11-13 | Kraftwerk Union AG, 4330 Mülheim | Transversely excited high energy laser |
| DE3136447A1 (en) * | 1981-09-14 | 1983-03-24 | Kraftwerk Union AG, 4330 Mülheim | LASER OF THE TE-TYPE, IN PARTICULAR HIGH-ENERGY LASER |
| FR2519812A2 (en) * | 1982-01-14 | 1983-07-18 | Comp Generale Electricite | GAS LASER EXCITED BY DISCHARGE CAPACITORS |
| DE3232024A1 (en) * | 1982-04-16 | 1983-10-20 | Kraftwerk Union AG, 4330 Mülheim | ARRANGEMENT FOR ADAPTING PULSE SHAPING NETWORKS TO THE REQUIREMENTS OF THE EXCITATION CIRCUIT OF A TE-HIGH-ENERGY LASER SYSTEM |
| DE3314157A1 (en) * | 1982-04-19 | 1983-12-08 | Kraftwerk Union AG, 4330 Mülheim | Excitation circuit for laser systems, especially for TE high-energy lasers, with adjustment of the pre-ionisation |
| JPS59500591A (en) * | 1982-04-19 | 1984-04-05 | シーメンス、アクチエンゲゼルシヤフト | Excitation circuit of laser equipment, especially TE type high power laser equipment, in which pre-ionization adjustment is carried out |
| DE3232225C2 (en) * | 1982-04-19 | 1986-11-20 | Kraftwerk Union AG, 4330 Mülheim | Device for generating fast, pulsed capacitor discharges in a laser |
| DE3313811A1 (en) * | 1983-04-15 | 1984-10-18 | Siemens AG, 1000 Berlin und 8000 München | TRANSVERSALLY EXCITED GAS LASER |
| DE3335690C2 (en) * | 1983-09-30 | 1986-03-27 | Lambda Physik GmbH, 3400 Göttingen | Device for generating high-power, high-voltage pulses with a high repetition frequency |
| JPS61137380A (en) * | 1984-12-10 | 1986-06-25 | Toshiba Corp | Lateral-excited gas laser oscillator |
| JPS61168276A (en) * | 1985-01-21 | 1986-07-29 | Mitsubishi Electric Corp | Voiceless discharge type gas laser |
| JPS61170087A (en) * | 1985-01-23 | 1986-07-31 | Mitsubishi Electric Corp | Silent discharge type gas laser device |
| JPH06105807B2 (en) * | 1986-05-08 | 1994-12-21 | 三菱電機株式会社 | Laser excitation device |
| DE3621005C2 (en) * | 1986-06-23 | 1993-12-09 | Lambda Physik Gmbh | Circuit for autonomous pre-ionization in a pulsed gas laser |
| GB8626751D0 (en) * | 1986-11-10 | 1986-12-10 | Dijk J W | Lasers |
| DE3852630T2 (en) * | 1987-08-31 | 1995-05-04 | Acculase Inc | EDELGAS HALOGEN EXCIMER LASER. |
| US4905250A (en) * | 1987-11-13 | 1990-02-27 | The European Atomic Energy Community | Pre-ionizing electrode arrangement for a gas discharge laser |
| DE68927568T2 (en) * | 1988-09-27 | 1997-04-17 | Yazaki Corp | Discharge tube |
| GB8827702D0 (en) * | 1988-11-28 | 1988-12-29 | Marconi Gec Ltd | Electric discharge apparatus |
| JPH0322388U (en) * | 1989-07-14 | 1991-03-07 | ||
| US5166574A (en) * | 1989-07-14 | 1992-11-24 | Yazaki Corporation | High-tension cable device |
| EP0532751B1 (en) * | 1991-02-08 | 1995-05-03 | Mitsubishi Denki Kabushiki Kaisha | Transverse discharge pumping type pulse laser |
| US6456643B1 (en) | 1999-03-31 | 2002-09-24 | Lambda Physik Ag | Surface preionization for gas lasers |
| US6650679B1 (en) | 1999-02-10 | 2003-11-18 | Lambda Physik Ag | Preionization arrangement for gas laser |
| US6757315B1 (en) | 1999-02-10 | 2004-06-29 | Lambda Physik Ag | Corona preionization assembly for a gas laser |
| US6671302B2 (en) | 2000-08-11 | 2003-12-30 | Lambda Physik Ag | Device for self-initiated UV pre-ionization of a repetitively pulsed gas laser |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA927465A (en) * | 1969-08-29 | 1973-05-29 | Hale Martin | Molecular gas laser energized by resistorless electrodes |
| FR2120191A5 (en) * | 1970-03-23 | 1972-08-18 | Comp Generale Electricite | |
| US4150343A (en) * | 1975-01-10 | 1979-04-17 | Lasag Ag | Method for generating laser pulses by means of a gas laser and apparatus for carrying out the method |
| CA1016641A (en) * | 1975-02-28 | 1977-08-30 | Michel Blanchard | Driving circuit for double discharge grid tea co2 lasers |
| NL7701389A (en) * | 1977-02-10 | 1978-08-14 | Stichting Fund Ond Material | GAS LASER SETUP. |
| DE2737226B2 (en) * | 1977-08-18 | 1979-06-28 | Eltro Gmbh, Gesellschaft Fuer Strahlungstechnik, 6900 Heidelberg | TEA laser amplifier |
| DE2932781C2 (en) * | 1979-08-13 | 1985-10-31 | Kraftwerk Union AG, 4330 Mülheim | Device for generating rapid, pulsed capacitor discharges in a laser |
-
1980
- 1980-09-22 DE DE19803035730 patent/DE3035730A1/en not_active Withdrawn
-
1981
- 1981-01-01 AR AR286785A patent/AR227437A1/en active
- 1981-09-10 EP EP81107155A patent/EP0048407A1/en not_active Withdrawn
- 1981-09-21 IL IL63897A patent/IL63897A0/en unknown
- 1981-09-21 AU AU75518/81A patent/AU539326B2/en not_active Ceased
- 1981-09-21 BR BR8106008A patent/BR8106008A/en unknown
- 1981-09-21 JP JP56149305A patent/JPS5788789A/en active Pending
- 1981-09-21 CA CA000386280A patent/CA1159937A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4718072A (en) * | 1983-12-29 | 1988-01-05 | Enea - Comitato Nazionale Per La Ricerca E Lo Sviluppo Della Energia Nucleare E Delle Energie Alternative | Corona discharge preionizer for gas laser |
Also Published As
| Publication number | Publication date |
|---|---|
| BR8106008A (en) | 1982-06-08 |
| DE3035730A1 (en) | 1982-05-13 |
| JPS5788789A (en) | 1982-06-02 |
| AU7551881A (en) | 1982-04-01 |
| AR227437A1 (en) | 1982-10-29 |
| IL63897A0 (en) | 1981-12-31 |
| AU539326B2 (en) | 1984-09-20 |
| EP0048407A1 (en) | 1982-03-31 |
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